Pull both calipers, & disassemble them. Sandblast the castings & check out the bore & the pistons. If the bores are crusty, you can probably hone them & clean everything up, buy new pistons & rings if needed - very cheap, & VERY easy to do. Then paint everything & reassemble. I rebuilt mine for my AAR & both pistons were stuck in place, so I hit each one with a blow-gun to the inlets but made the mistake of not holding a towel over the pistons. One shot-out & hit my garage ceiling & blew fluid all over. Duh!